1. Technical Field
This application relates generally to Code Division Multiple Access (CDMA) communication techniques, and more particularly to methods and apparatus for reducing power consumption in a CDMA communication device which utilizes “bursty” communication techniques.
2. Description of the Related Art
Wideband Code Division Multiple Access (WCDMA), CDMA2000, and Interim Standard (IS) 95 are respectively third generation (3 G), two-and-a-half generation (2.5 G), and second generation (2 G) public land mobile telecommunication systems that use CDMA communication techniques. Various standardization bodies set and publish such standards for CDMA communication, each in their respective areas of competence. For instance, the Third Generation Partnership Project 2 (3GPP2) sets and publishes communication standards for CDMA2000. Within the scope of a particular standardization body, specific partners set and publish standards in their respective areas.
Known CDMA communication techniques require that a mobile station (MS) simultaneously transmit and receive signals over a traffic channel during a communication session with a base station (BS). Such requirements are undesirable from the standpoint of power consumption, especially for “bursty” communications where data or other signals may be communicated in a somewhat discontinuous and/or sporadic fashion. Minimizing power consumption is a relatively important objective for MSs, especially when they are battery-powered and equipped with a relatively small battery source.
When there is communication inactivity during a session (e.g. no data packets or voice signals to transmit), the MS is still required to transmit frames of lowest agreed upon rate to maintain the session. For a data session, if a predetermined amount of time (such as twenty seconds) elapses with no communication activity between the BS and the MS, the session may be terminated by the BS. In one particular technique, a CDMA MS is required to transmit RLP idle frames at the lowest rate when the MS has no RLP data or RLP control frames to send during an active packet data session. Similarly, the MS is required to send the lowest rate frames during a voice call when there is no voice, audio, or signalling activity. As apparent, the MS and the network may undesirably spend a significant percentage of the overall session in “overhead” or “maintenance” in the exchange of idle frames. In addition, if a MS and BS agree to use coherent communication on the reverse link, this may require that the MS send a pilot channel during a voice call or packet data session regardless of the rate of the traffic channel. The reverse pilot channel also includes fast forward power control channel which is used by the BS to adjust its transmit power. Since the power of the reverse pilot channel is relatively high in comparison to the lowest rate reverse traffic channel, the MS may consume a significant amount of power just by keeping its transmitter on when there is no data to send.
Accordingly, there is a resulting need for reducing power consumption in a CDMA communication device.